When most of today's parents were growing up, the common wisdom about television viewing was not to sit too close to the screen or you’d go blind. There was relatively little in the way of children’s programming: Sesame Street, which turned 35 this year, was in its infancy and there were a few cartoons, as well as Captain Kangaroo, Mr. Rogers and Romper Room.

How times have changed. In the years since then, children’s programming has exploded. Now whole networks are devoted to young viewers.

And, interestingly enough, something else has exploded: Attention Deficit Hyperactivity Disorder, or ADHD, a behavior condition that now affects from 4 percent to 12 percent of U.S. children. ADHD is characterized by the inability to focus, listen, and complete tasks and schoolwork. Many children are medicated to control the condition.

When it comes to TV, says Dr. Dimitri Christakis, a pediatric researcher at Children’s Hospital and Regional Medical Center in Seattle, concerns over eyesight should be the least of parents' concerns. Instead, he contends that ADHD and the onslaught of children’s programming, along with DVD players and portable TVs that make viewing possible anywhere anytime, may very well be linked.

Study finds increased risk from TVChristakis is the lead author of a study published in the journal Pediatrics in April that suggests TV viewing in very young children contributes to attention problems later in life. “The study revealed that each hour of television watched per day at ages 1 through 3 increases the risk of attention problems by almost 10 percent at age 7,” says Christakis.

The study attempted to control for attributes of the home environment, such as cognitive stimulation and emotional support, but a key factor was left out: the content of the programs children watched. Christakis says this aspect should be studied in more detail at some point, but he maintains that it’s not the message of the program that’s likely the culprit — it’s the visual tactics used.

Christakis and others in the field, such as Jane Healy, an education psychologist in Vail, Colo., and author of "Your Child’s Growing Mind: Brain Development and Learning from Birth to Adolescence," believe common programming tactics designed to capture a child’s attention can have a deleterious affect on brain chemistry.

Healy says overstimulation from rapid scene changes and other programming tactics may throw off the balance of the body's catecholamine system, which is responsible for carrying communications between nerves.

“It has to do with neurotransmitters in the catecholamine system — dopamine and norepinephrine,” she adds.

Real life becomes slow and boringChildren’s programmers use a technique called the “orienting reflex," known as OR, to capture and keep a child’s attention. OR works in this way: If we see or hear something the brain doesn’t recognize as the correct sequence or a typical life event — such as a dancing alphabet or quick zooms and pans, we focus on it until the brain recognizes that it doesn’t pose a threat. The problem with watching too many programs that rely on OR is that real life becomes slow and boring by comparison.

“We think that with continued exposure to high intensity, unrealistic action, you’re conditioning the mind to expect that level of input,” Christakis explains. When the child doesn’t get the fast-paced input that television provides, he or she becomes bored and inattentive.

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“It used to be that as educators we talked about the 'two-minute mind,'" says Healy. "Now it’s the 30-second mind." Of course, having an extremely short attention span makes listening, problem solving and learning to read difficult.

Genetics may play key role
While the implications of Christakis’s study are intriguing, not to mention frightening to all those decent parents who consider it a good day when their children sit contently watching Sesame Street and perhaps even a Baby Einstein chaser, they may also be a bit sensationalistic, says ADHD expert Dr. David Rabiner of Duke University.

“At this point there’s a compelling body of evidence that suggests that it’s genetics that plays the biggest role in ADHD,” he says. “Not bad parenting.”

While some research has been done to determine if there are links between ADHD and environmental factors, as well as nutrition, sleep disorders, exposure to toxins and certain prenatal conditions, Rabiner says the connections have consistently been found to be weak or nonexistent.

Instead, Rabiner attributes the rise in ADHD to more awareness of the condition and slightly relaxed criteria for diagnosis.

“I think it’s a gross misunderstanding of the recent study to jump to the conclusion that television watching leads to ADHD. The study doesn’t prove anything of the sort,” says Rabiner, who notes that the scale used in the study to determine if children who had watched TV later developed “attention problems” cannot be compared to the standards that a professional would use make a diagnosis.

Rabiner advises parents to limit the amount of television their children watch for a variety of reasons, but says they should make the choice independent of any worries that TV causes ADHD.

Christakis agrees — sort of. “Our study doesn’t prove a link between clinical ADHD and television viewing,” he says. “But I don’t even think that’s the most important point here. As parents, the most important thing is for us to do everything we can environmentally to encourage our children to focus as much as they are genetically endowed to.”

What's a parent to do?So should parents throw the TV out the window? Healy and Christakis offer these more moderate suggestions:

Parents should keep TV viewing to a minimum, if not eliminate it, for a child's first two years. This is also the recommendation of the American Academy of Pediatrics. “There are videos that claim they’re good for children’s minds, but there is absolutely no evidence that any program is good for young children,” says Christakis.

For children older than two, limit total screen time (TV, computers and video games) to an hour of carefully selected programming per day. Slow-paced shows are preferable to fast-paced ones.

Reduce the background noise of TV as much as possible. Researchers believe background noise interferes with a child’s ability to concentrate on a problem and decide on a reasonable behavior or train of thought.

Encourage your children to learn through their hands and bodies. “It’s better to touch and smell an apple rather than watch one on the television or computer screen,” says Healy.

Talk to your child and listen instead of allowing any screen to talk to him or her. This communication is crucial in the development of language and interpersonal skills. “If you skip over early language or shortchange it because you’re watching television so much, you may never get it back,” warns Healy.

Victoria Clayton is a freelance writer based in California and co-author of the forthcoming book "Fearless Pregnancy," due out in November from Fair Winds Press.